A 61-year-old man presented with acute, painful loss of vision in the left eye due to a central retinal artery occlusion. Fluorescein angiography confirmed the central retinal artery occlusion and also identified a nasal posterior ciliary artery occlusion. CT scanning revealed a left medial orbital mass with adjacent ethmoid sinusitis. Transnasal ethmoid biopsy disclosed mucormycosis. A left external ethmoidectomy, maxillectomy, and orbital exploration were performed, after which the patient was treated with daily intravenous amphotericin B for six weeks. Coexistence of retinal and nasal posterior ciliary artery occlusion due to mucormycosis may relate to their common origin from the ophthalmic artery. Treatment without exenteration was successful.